A great many manufacturing processes and mineral recovery procedures are characterized by generation of liquid form wastes, some of which are hazardous. Commonly, the liquid wastes are discharged to an encatchment, such as, for example, tailing ponds and sludge pits wherein the solid contents settle out and the clarified liquid is withdrawn, or the liquid is evaporated. Some liquid wastes are relatively permanent and must be solidified. Others should be solidified. Although industry has long been concerned with disposal of hazardous liquid wastes, more and more public attention is being directed to shortcomings believed to exist.
In particular, practices that long have been accepted by the public, such as discharge of highly acidic mine waters into the local streams are now being challenged. In addition, it is now appreciated that water soluble polutants go into solutions that can migrate many miles subterraneously through porous strata underlying a waste liquid encatchment. In consequence, many industries find themselves in a position where their liquid or slurry waste products must be connverted into some that retains the toxic components of the liquid in place. This very thought suggests conversion of liquid wastes into some solid form, wherein the water itself is in water insoluble form physically trapped in a solid mass of very low permeability. Liquids may be solidified permanently and readily through conduct of some chemical reaction appropriate to the composition of the particular liquid.
Thus, for example, an aqueous liquid of semi-liquid waste material can be solidified by mixing such material with appropriate amounts of a hydraulic cement, after which the mixture is allowed to set. For further understanding of such liquid solidification procedures, reference is made to U.S. Pat. Nos. 3,980,558; 4,226,630; and 4,338,134. Practice of the present invention employs the concept of solidifying liquid waste. In specific, this invention relates to an in situ solidification of the standing bodies of liquid in waste liquid catchments such as, for example, sludge pits, settling ponds.
The approach adopted by the inventor hereof toward solidifying a standing body of liquid bears a distinct resemblance to concepts and equipment heretofore employed by the art to convert unstable soils into more stable form by introduction of a pulverulent ground stabilizing agent. In brief, a hollow tool, often formed as a drill head, is extended below the ground surface to a desired locale, then binding agent is introduced into the unstable strata from nozzle apertures in the tool so that the binding agent becomes mixed with the earth material. For further understanding of this technique, reference is made to U.S. Pat. Nos. 3,540,837 and 4,058,986.
It is now been found possible to stabilize waste liquid catchments waste effectively and efficiently by such a technique.